Who inspired some of the thoughts in the declaration of independence with his ideas from the enlightenment era?

Thomas Jefferson used the thoughts first penned by John Locke while writing the Declaration of Independence. The phrase "life, liberty, and pursuit of happiness," was an idea first considered by Locke in his Two Treatises on Government.

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."